I do that combining numbers to get tens, but you have to know other math cats first.
Who the heck cares how *comfortable* the kids feel with it.
They need to memorize their basic math facts because memorizing 9+6=10 and being able to instantly recall it, is FAR quicker than grabbing a pen and paper and writing it all out and taking a minute to calculate it.
They will discover the short cuts once they get the basics down.
I made my kids memorize their math facts and I would not let them use a calculator until they were in Algebra 1 of Saxon Math.
All of them have superior math skills. All three of them are in STEM fields.
You must have gone to a publik skrewl.
other math cats first = other math facts.
Good Lord, I’m tired today.